Jordy van Sambeeck

Chapter 1 10 Background and physiology of the patellofemoral joint The scope of this thesis is on patellofemoral instability and includes diagnostics, osteotomies and outcome of treatment of patellofemoral instability. The aim is to optimize the treatment of patients with patellofemoral instability by increasing knowledge on certain aspects of treatment, on the continuous track to the best possible care. The patella (kneecap) is the largest sesamoid bone of the human skeleton. The patella articulates with the trochlea of the femur and increases the lever arm of the extensor mechanism, thereby increasing the extension moment of the quadriceps muscle. The articulation between the patella and the femoral trochlea is called the patellofemoral joint. The patellofemoral joint is aligned by bony structures and is surrounded by soft tissue structures such as the quadriceps tendon, patellar tendon, medial patellofemoral ligament (MPFL), lateral patellofemoral ligament and the retinaculum of the knee (figure 1 and figure 2). Figure 1. The patella surrounded by its soft tissue structures.